Method of flash smelting sulfide ores

ABSTRACT

A fine-grained concentrate of sulphide ore is suspended by a special dispenser into which a heated downward flow of air, air enriched with oxygen or oxygen containing gas in a vertical reaction shaft of a furnace to oxidize the non-oxidic metal compounds in the concentrate. The gases and the flue dust are separated from the solids which form a smelt on the bottom of the furnace consisting of a matte and a slag on the matte. The partial pressure of sulphur in the gases obtained from the oxidizing smelting carried out in the reaction shaft is increased and/or the partial pressure of oxygen is decreased, in which case the metal oxides contained in the flying dust are converted into corresponding sulphides and most of the iron contained in the slag retains the valence of 2.

D United States Patent 1 91 1111 3,790,366

Bryk et al. Feb. 5, 1974 [5 METHOD OF FLASH SMELTING SULFIDE 2,090,386 8/1937 Ferguson 75/9 ORES 2,503,555 4/1950 Lyrken 75/9 2,746,859 5/1956 McGouley 75/1 1 Inventors: Part y ink Jorma B. 3,306,708 2/1967 Bryk 423/571 Honkasalo, Westend; Roll E. 2,219,411 10/1940 Carlsson 75/23 Malmstrom; SiIIlO A. Maklplrttl, 2,868,635 l/ 1959 Aannerud 75/23 both of Pori; Toivo A. Toivanen, Harjavalta; Aflltonen, P017, Primary Examiner-15. Dewayne Rutledge all of Finland Assistant Examiner-Peter D. Rosenberg Attorney, Agent, or Firm-Albert M. Parker; Harold [73] Asslgnee' g gtg oyottokumpu Haidt; Lorimer P. Brooks; G. Thomas Delahunty;

A Alfred L. Haffner, Jr.; Charles G. Mueller [22] Filed: Jan. 13, 1970 [21 Appl. No.: 2,471 7] RA A fine-grained concentrate of sulphide ore is sus- [30] Foreign Application Priority Dam pended by a special dispenser into which a heated Jan I 4 1969 Finland 104/69 downward flow of air, air enriched with oxygen or 0xygen containing gas in a vertical reaction shaft of a furnace to oxidize the non-oxidic metal compounds in [52] US. Cl 75/23, 75/7, 75/74, the concentrate. The gases and the flue dust are sepa 75/110 423/571 1 df th 111 h hf 11 th b 1 51 1111. CL... C22b 15/00, C22b 1/02, c221 15/04 e e S a f g f 58 Field of Search 75/23, 24, 25, 26, 34, 21, mm mace 3 a s as 75/72 73 6 7 23/224 the rnatte. The partial pressure of: sulphur 1n the gases obtained from the OXldlZlng smelting carried out in the reaction shaft is increased and/or the partial pressure [56] References Cited of oxygen is decreased, in which case the metal oxides UNITED STATES PATENTS contained in the flying dust are converted into corre- 2,209,33l 7/1940 Haglund 75/9 sponding sulphides and most of the iron contained in Zeisbrg lag valence of 2 3,386,815 6/1968 Gorling 75/9 2,984,561 5/1961 Amdur 75/9 9 Claims, 2 Drawing Figures METHOD OF FLASH SMELTING SULFIDE ORES BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method to be used in connection with flash smelting of sulphide ores.

2. Description of the Prior Art In the flash smelting method of copper ores, finegrained copper concentrate is suspended, together with air heated to a high temperature or gas containing oxygen or air enriched with oxygen, by a special disperser, while moving downwards in a vertical shaft, at which time the non-oxidic metal compounds contained in the concentrate become oxidized.

Due to the heat content or sufficient oxygen concentration of the combustion air, so high a temperature is obtained in the shaft by using the reaction heat that the solid materials melt.

The gases and solids are separated from each other, and a melt separates on the bottom of the so-called separation section of the furnace. The surface layer of the melt is formed by slag and the second layer by sulphide matte and the bottom layer of metal. At times slag and matte are removed from the furnace.

The gases and the flying dust following them escape from the furnace space along the so-called rising tube into, for example, the waste heat boiler, where their temperature is lowered, after which the flying dust is separated from the gases in an electric filter.

The recovered oxidized or sulphated flying dust is returned to the smelting process, where it forms a socalled circulating load and takes its melting heat from the burning components of the actual concentrate, thus decreasing the smelting capacity of the shaft.

The copper content of the slag formed in the smelting of copper ores is of great importance for the economy of the smelting process. The effect of the copper content of the matte formed in the smelting process on the copper content of the slag can be clearly seen as in direct dependence; the more copper there is in the matte, the higher copper content in the slag as well.

One alternative is to carry out the smelting in such a manner that the copper content of the matte stays low, in which case the copper content of the slag is also low.

However, the result of this is that a great amount of slag is left to be treated in the converter, which again gives a great circulating slag load to the furnace.

When copper matte with a higher copper content has been desired in flash smelting, the slag has been treated separately, by keeping it molten, for example, in an electric furnace and by adding, for example, pyrite to sulphidize the copper.

In this case, the slag may have originally contained as much as l-4 per cent copper, and the aim is to bring the copper content to 0.4 per cent or less.

In the so-called Worcran smelting method, shown in US. Pat. Nos. 3,326,671 and 3,463,422 and developed by Austrailian H.K. Worner, a reverberatory-type furnace equipped with a special bottom form is used for the smelting of copper ores. The concentrate is fed to the middle of the furnace, and matte with a copper content of more than 80 percent, or copper, is removed at one end of the furnace, the furnace atmosphere being oxidizing. At the other end of the furnace, pyrite is fed onto the surface of the slag and the necessary heat is given by an oil burner with a reducing flame. The gases escaping from the furnace will contain some 9-12 percent SO as well as oxygen and nitrogen.

Experiments have also been made regarding the ef' fect of several metal sulphides on recovering copper in the form of a sulphide from the slag. According to these experiments, the most effective sulphidizer is calcium sulphide.

It has been noted that iron with a valence of 3 is formed in the smelting process of copper ores. This iron, or magnetite as such, and when separated, greatly increases the viscosity of the slag and thereby slows down the separation of possibly sulphidized copper as matte from the slag. Therefore attempts have been made to reduce the magnetite by different methods, by adding coal to the surface of the slag and/or adding also pieces of cast iron containing carbon into the furnace. Furthermore, if the magnetite content is sufficiently high it tends to separate in a solid form from the melt or semi-melt (dusts etc.) at the used temperatures and thus form growths at certain points.

SUMMARY OF THE INVENTION According to the invention the ratio of the partial pressure of sulphur vapor to the partial pressure of oxygen is increased in the gases obtained from the oxidizing smelting in the vertical reaction shaft of a furnace to convert the metal oxides contained in the flue dust following the gases into corresponding metal sulphides and to retain most of the iron in the slag in a bivalent state.

The inconveniences and difficulties caused by the prior smelting methods are eliminated when sulphide ores are smelted in accordance with the present invention. Furthermore, it is possible to control the process better than before, to increase the capacity of the apparatus and to decrease the amount of metal lost in the slag.

FIG. 1 is a schematic view in cross section of apparatus suitable for performing the method of the invention FIG. 2 is a top view of the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The gases emerging from the reaction shaft are treated reducingly enough with suitable materials so that the oxygen pressure of the gases is lowered and respectively so much elemental sulphur is reduced from the sulphur dioxide that the pressure of sulphur vapor in the furnace atmosphere is sufflcient to cause the sulphidizing of both the metal oxides contained in the flying dust (Cu, Ni, Co, Zn, Pb, etc.) and the copper contained in the slag. In other words, the pressure of the sulphur vapor is as high or higher than the vapor pressure of the sulphur in the sulphide compounds of metal at the temperature in question, in which case the said sulphides are, under these conditions, stable, and copper, for example, can be separated from the slag into the matte in the form of a sulphide.

In practice this takes place in the following manner: so much fuel, sufficiently dispersed, for example, carbon dust, liquid or gaseous hydrocarbons, saw dust, etc., is added to the gases emerging from the reaction shaft that the reduction mentioned above is obtained in the gases; if needed, fuel is also added for the purpose of producing heat.

The pressure of the sulphur vapor of the furnace gases can in principle be increased also by feeding elemental sulphur into the gases emerging from the reaction shaft; at the temperatures in question this sulphur immediately vaporizes creating the desired atmosphere. Most of the time it may be, however, most advantageous to create the sulphur vapor atmosphere with the help of some fuel from the sulphur compounds contained in the furnace gases themselves.

The reduction of sulphur dioxide must be carried out at least so far that the sulphur pressure of the furnace atmosphere is sufficient to carry out the desired sulphidizing. This can be easily regulated by regulating the amount of fuel.

With the method according to the present invention, by sufficiently increasing the reduction, most of the sulphur contained in the sulphur dioxide can also be converted into elemental sulphur and recovered by cooling the gases.

In certain cases this is most advantageous because the recovery and treatment of elemental sulphur often gives a remarkably more economic result than the manufacture of sulphuric acid and the devices required for it.

When the method according to the present invention is used, a remarkable advantage is also gained in regard to the factors having an effect on the pollution of the open air in connection with the treatment of the exhaust gases.

The flying dust, which has so far been ineffective material that loads the smelting in the flash smelting process, gives a considerable amount of heat in the form of sulphides and thus increases the smelting capacity of the shaft.

When the metals of the flying dust are in the form of sulphides, the conventional flotation method of sulphide minerals can be used to separate them, which would not be possile in the case of respective metal oxides.

By appropriately regulating the degree of reduction of the reaction gases emerging from the shaft, the final S content of the gas can also be regulated, for example, keeping an eye on the optimal SO, content required by the devices used in the process of manufacturing sulphuric acid. This can be done, for example, when the capacity of the manufacturing devices of sulphuric acid is not sufficient for the treatment of the entire amount of gases obtained from the smelting process. In this case the sulphur content of the extra S0 can be recovered in the form of elemental sulphur in the method according to the present invention.

Because the copper content of the slag can be main tained sufficiently low with the reduction of the furnace gases, the smelting of copper ore can be carried out in the reaction shaft in an atmosphere more oxidizing than before. Thereby is created a matte richer in copper without simultaneously increasing the losses of copper in the slag. Neither can magnetite, which has so far prevented these attempts, cause any difficulties.

By carrying out the flash smelting of copper concentrate, with the method according to the present invention, in a shaft in a more oxidizing atmosphere than ordinarily used, in which case a matte rich in copper 80 percent) or a raw metal is formed, the amount of iron blown into a slag in the converter and also of the slag formed in it can be greatly decreased, thus essentially decreasing losses of copper occurring through it and possibly the amount of converter slag to be treated separately in order to recover copper.

Under suitable conditions it is possible, with flash smelting to carry out the oxidation in the shaft so far that a melt containing mainly metallic copper and/or possibly some Cu S (white metal) is formed on the bottom of the furnace, and on the top of this melt the actual layer of slag, the atmosphere of which is, according to the present invention, sufficiently reducing to keep the copper content of the slag as low as desired.

The result of this is that most of the conventional converter work can be left out, and thus one very inconvenient stage of work can be decreased with the method according to the present invention, which is a very remarkable advantage both economically and technically.

The smelting carried out in the shaft need not necessarily be a so-called autogenic flash smelting, but fuel can also be fed into the shaft to obtain the smelting temperature. This is much closer to the conventional smelting of copper ores, but the method according to the present invention can as well be applied to a case like this.

The construction of a flash smelting furnace according to US. Pat. No. 2,506,551 has proven most advantageous in the application of the method according to the present invention because in this furnace the gaseous atmospheres of the vertical reaction shaft and the horizontal separation section are separate from each other, and a continuous flow of gas in the same direction effectively maintains this situation.

The sulphur-containing atmosphere crreated with the method according to the present invention above the melt has proven most advantageous in the flash smelting process of copper ores. The following examples give the balance of a flash smelting carried out in the conventional manner and the balances of smeltings including the reduction in accordance with this invention.

A furnace system like the one presented in FIG. (1) was used in the test smeltings. The diameter of the vertical reaction shaft (a) was 1.20 m and height 6.5 m. The lower section of the reaction shaft was connected with the separation, or lower, furnace (b), the dimensions of which were the following: width 1.20 m, height 1.00 m and length 3.80 m. Opposite the reaction shaft, on the top of the lower furnace, there was a vertical shaft uptake (0) for removing the exhaust gases. The dimensions of this shaft were the following: diameter 0.76 m and height 4.70 m.

In order to cover the relatively great losses of heat due to the small scale of the furnace, butane was used as additional fuel in the experiments (its composition was the following: 17.24 percent of weight H and 82.76 percent of weight C). The additional fuel was fed in a raw state partly through the cover of the reaction shaft and partly from below the shaft through the wall of the .lower furnace (FIG. (1), d).

Butane was also used to create the reducing conditions in the lower furnace (b) and the uptake in the test series described here. It was fed raw intothe furnace at the points (e) and (1) indicated in FIG. (1).

The concentrate feed, slag materials and combustion air were fed through the cover of the reaction shaft into the reaction space with the help of speciallyconstructed suspension dispersers.

Melt products matte and slag phase were removed from the furnace periodically after sufficient seperation periods and cast into chill molds or granulated with the help of sprays of water.

The gases emerging from the furnace and the flying dust following them were led through the rising tube into the waste heat boiler, were their temperature (l250-1300C) was lowered to 400C. After this, the flying dust was removed from the gases with electric filters.

For a partial recovery of sulphur, the gases were led from the electric filters into a condensation boiler 150C or gases reduced, for example, in the uptake into the ratio vo1-% -(H +H S+CO+COS)/2SO -=1 in a conventional manner to a catalytic circuit and condensers double catalysis: 400C and 210C.

The proceeding of the experiments was observed by carefully measuring and analyzing the amounts of material fed into the furnaces and removed from them.

The changes in the matte and slag content of the lower furnace were observed by taking samples from the melt, from points between the bottom and surface, and at some 500 mm from each other, at regular intervals for a chemical analysis, microsonde and other X-ray analyzers.

The composition of the gas phase was measured FIG. (1) with a gas chromatographic analyzer at points (g) and (h) of the reaction shaft and at point (k) of the uptake.

The samples of solid and molten materials in the reaction shaft and the uptake were taken at the same points as the gas samples.

The temperatures of the system were continuously automatically measured and in addition at the points where samples were taken at the times they were taken.

During the testing periods the reaction shaft was operated so that the gas temperature of measuring point (h) of the shaft FIG. (1) was 1300i10C.

Table 1 sulphidizing of the flying dusts as a function of the copper content of the matte was to be started in the flash smelting process.

EXAMPLE l-l Conventional Smelting method All the tests series except the last (III-1) are based on the same conditions of the reaction shaft amounts fed, temperatures, cooling, combustion technology, etc.

The amount of conentrate feed was 503 kg/h. The amount of butane in the reaction shaft was 23.2 kg/h. The combustion air for the concentrate and the butane, 965 Nm had been pre-heated to the temperature of 500C.

' In the example I-l, the amount of heating fuel in the lower furnace was 42.7 kg/h. The purpose was to regulate the combustion air of the lower furnace so that the oxygen pressure of the gas phase would settle at the same as that of the gases emerging from the reaction shaft: Theamount ofairused in the experiment was 504 Nm The length of the testing periods was usually some 5 days.

The material balance obtained with the conventional smelting method, and an analysis of its main components is seen in Table 1.

Amounts and analyses of main components Balance Amounts of material kg component Sum Cu Fe S 0 SiO,

Cu concentrate 66007 12028 23485 22434 4725 Sand 11738 109 47 10336 Bowl (1) 77745 12028 23594 22434 47 15061 Matte 10857 8317 217 2123 30 16 Slag 43485 1456 20006 115 6542 11929 Flying dust 12279 2255 3359 408 1518 3131 Total (2) 66621 12028 23636 2646 8090 15076 Difference (1H2) 0 -42 19788 -8043 l5 Analyses weight-9 Concentrate 18.22 35.58 33.99 7.16 Sand 11.93 11.40 118.06 Matte 76.60 2.50 19.55 0.28 0.15 Slag 3.35 46.01 0.27 15.05 27.43 Flying dust 18.37 27.36 3.32 12.37 25.50

l k ir' xfir i'nienis to be "651666 atrr'tvrmrrfeasger matte, the specific curve of the testing shaft with three in which Cu-% is the copper content of the matte in weight percentages. Function F(P0,) has the Theaiialys es of the additional components, the gas phase balances and analyses of the reaction shaft and the lower furnace, and the heat balances of the processes are given in Appendixes I, II and 111.

According to Appendix II the oxygen pressure of the gas phase at measuring point (12) of the reaction shaft in the test operation of this example is 1.17 X 10' atm. (in the matte 76.6 Cu). The sulphur content of the flying dust is only 3.32 so that there is obvious danger of the uptake getting clogged. In the case of leakages of air the waste heat boiler would be easily polluted because of sulphate-oxide clinkers, and the dust to be returned in the process would become even lower in fuel value than before.

The slag formed in the process was ordinary Fe olivine slag (in which Zn olivine appeared as an independent mineral in a consolidated state). No crystallized magnetite appeared in the -molten slag because the amount of (Fe iron with a valence of 3 was sufficiently low, that is, 9.83 The copper content of the siig" was considerable (3.35%). According to the X-Ray surface analyzer the copper contained in the slag was in the form of metallic copper, Cu O and sulphide matte. Because the process was operated with great amounts of dust in order to study the flying dusts, the distribution of the side components does not correspond to the great scale. The component distribution in relation to slag was the following weight-% of the feed 79.7 C; 34.2 Ni; 41.5 Zn; 2.9 Ag; and 0.2 Au. The sulphide matte contained some percent metal phase. The composition of the phase was weight-% 96.7 Cu; 0.18 Fe; 0.20 Zn; 0.80 Ni; 0.70 Co; and 1.50 S.

EXAMPLE "-1 Partial reduction and sulphidizing in the uptake The balance of materials in this test operation was exactly the same in the reaction shaft and the lower furnace (b) as in the previous example. However, when the specific curve of the reaction shaft was determined, it was noted that the growths of the material in the uptake did not appear if the oxygen pressure of the gas phase at measuring point (h) FIG. 1 (P 5 X atm. (1300C).

Because of the said FIGURE, 16.9 kg of butane per hour was fed to feeding point (1) of the uptake for the reduction.

Because of the endothermic sulphidizing reactions of the flying dusts the temperature of the gas phase in the uptake decreased to 1250": 10C. Simultaneously the amount of sulphur in the flying dust increased from 3.32 to 18.29 percent S, the amount of oxygen respectiv'ely decreasing (12.4 2.7 percent 0).

The amount and analyses of the flying dust and the gas phase balance with its analysis and the heat balance are given in Appendixes I, II and Ill. The oxygen pressure of the gas phase was, at the temperature of 1250C, P0,=l.82 10*, and1 4.18 '10- aim. The fuel value of the flying dust rose simultaneously the basis of the balance being the oxidation degree FeO, Cu O, ZnO from (298K) AH 32 Kcal/kg to AH +585 Kcal/kg.

ExAiZiE 11-2 used temperaturesln order to create an oxygen pressure of P 1.8 10- atm. at the temperature of 1250C, 19.29 kg of butane per hour was used as additional fuel in the gas phase in comparison to a conventional smelting method, in which case the total amount of fuel rose to 85.19 kg/h. The figures and analyses of materials of the obtained new smelting balance are given in Appendixes I, II and 111.

No essential changes have taken place in the compositions of the flying dust and matte. The partial reduction of the slag has slightly increased the amount of matte. The decrease in the amount of flying dust is mainly due to the growth of the particle size of the used sand, and a corresponding decrease in the amount of sand feed and the amount of dust resulting from it.

A considerable change take places in the slag, in which the proportionate amount of 3-valence iron decreases to some 4.5 percent, having been some 9.8 percent in the previous cases. The sulphur content of the slag increases slightly, but the copper content decreases considerably, to the proportionate amount of 0.5 percent Cu, having been 3.4 percent in the previous tests. The lengthening of the delay period from the used four hours did not lessen the copper content of the slag with the used degree of reduction of the gas. Metallic copper and copper matte was observed with a microsonde in minimal quantities only.

The distribution of the side component metals in the process did not essentially change in comparison with the previous figures.

. EXAMPLE 11-3 Partial reduction and sulphidizing in the lower furnace and the rising tube This test operation differs from the previous one (11-2) in that more reduction butane, an amount of 13 kg/h, isfed to the uptake point (1) in order to lower the oxygen pressure of the gas phase and to respectively increase its sulphur pressure.

Because of the increase of the sulphur pressure of the gas phase a complete sulphidizing takes place in the flying dust. The new amount and composition of the flying dust, the gas phase corresponding to the process, and the heat balances are given in Appendixes I, 11, and Ill.

nents, mainly S0 carried by the exhaust gases was 2.24 percent.

EXAMPLES Il-4 AND 11-5.

Partial reduction and sulphidizing in the lower furnace (b) reductionof gases in the uptake to a reduction ratio completely corresponding to the sulphur catalysis.

Examples 11-4 and 11-5 differ from the previous example 11-3 in that so much fuel is now added to the uptake that the reduction ratio to be catalyzed, namely, (H,+H S+CO+COS)/2SO, 1 is obtained the components are given in volume percentages.

In the test series 11-4 the increase of fuel compared with the previous test (II-3) was 13 kg/h of butane (or the total amount increased to 1 11.20 kg/h). The temperature of the gas measured in the uptake was 1250C. In the test series 11-5 the gases were taken from the uptake at the temperature of 1300C corresponding to the catalysis ratio. The additional amounts of fuel and air required for the increase of the temperature of the gas phase were 12.59 kg/h of butane and respectively 151.2 Nm lh of combustion air.

The gas phase and heat balances corresponding to each test series are given in Appendixes 11 and 111.

According to Table 2, by using a double catalysis the following percentages of the sulphur fed into the gas EXAMPLE 111-1 Feeding of sulphidized flying dust back into the 55 smelting system.

The test series was carried out in conditions exactly similar to those in example 1I-2.

The reduction butane was fed to the lower furnace at feeding point (e). The oxygen and sulphur pressures of phase in the reduction tests of the test series could be 5 the gasphase in the uptake at a temperature of 1250C recovered in the form of elemental sulphur: were P 1.80 X atm and P ,=3.64 10f "-2 about 28.6; "-3 about 60.1; and 11-4 about 93.9. atm. The feeding amounts of butane and air were 84.5 By using the most simple separation method, that is, kg/h and 1445 Nm /h respectively. condensation, the obtained amounts weight-% of The feeding amount of sulphides was 500 kg/h and elemental sulphur corresponding a temperature of 10 the portion of flying dust in it was 16 weight-%. 140C are the following: The products of the test operation together with their lI-2 about 1 1.7; "-3 about 26.9; and II-4 about 44.4. analyses and the gas phase and heat balances are given On an industrial scale these figures are somewhat in Appendixes I, II and III. higher because, depending on the cooling of the gases, The circulating flying dust load did not notably gliding takes place in a direction increasing the amount change the distribution of the side components in the of elemental sulphur, that, is catalytic direction. This melt products. The amount of zinc only sligtly incan easily be seen from the results obtained in the doucreased in the slag phase even though its feeding ble catalysis of the test series lI-4. amount increased some 57 percent in comparison to A. Catalysis at a temperatureof 400861; example I-l under the influence of the dusts.

Volume of gas 1586 Nm; P0,= 1.18 X 10" and 20 A considerable advantage is gained by feeding sulphi- P ,,=2.42 X 10 atm. dized flying dust compared with oxidic dust, thanks to Analysis vo1-% 2.67 H 5; 0.20 COS: 1.36 50;; the greater fuel value of the former. 12.29 CO and 83.65 N For example, in the test operation H the fuel value B. Catalysis at a temperature of 200C: of the flying dust was (at a temperature of C and Volume of gas 1577 Nm selective catalysis 25 taking the oxidation degree of F e0, Cu O and ZnO as a a basis): H 32 Kcal/kg and that of sulphidized dust S02 2H2O9) in the test operation Ill-l: H -640.4 Kcal/kg. When n y V0l-% e S 2; boiler leaks and the like occur, oxidic dust (containing 12.75 CO and 86.86 N some sulphur) may also occur sulphated in which case However, condensation is advantageous in special the dissociation heat of the sulphates must naturally be cases only, for example, when the capacity limit of a supplied in the reaction shaft. Let us mention as an ex- H SO manufacturer so demands. In most cases an adample the fuel values of dust obtained in production in ditional burning must be carried out after the condencases of boiler leaks: oxidic dust (4.8% S; 2.4% S10 sation in order to convert the S compounds into corre- A H 49.8 Kcal/kg; sulphated dust (22.6% 0) A H sponding oxides. 35 235.8 Kcal/kg; and partly sulphidized dust (23.1% S

"fig .,,.f;ble3 ,,Wfi,.,,. WWW..-

Yield of elemental sulphur in test operations Sulphur balance component Example "-1 11-2 11-3 .11 1 Feeding of sulphur to the separation process: kg/h 135.7 131.4 124.8 124,8 Yield of sulphur from the catalytic circuit: kg/h 38.0 37.6 75.0 117.2 Yield of elemental sulphur from the feed: '71 28.0 28.6 60.1 93.9 Amount of exhaust gases in a humid Mule: Nm"/h 1533.3 1538.7 1553.0 1566.6 Analysis of exhaust gases -Vnl-% s0,+11s,.+c0s+H,s 4.45 4.26 2.24 0 34 Yield of elemental sulphur from the feed at a temperature of C of the feed 1 1.9 11.7 26.9 44.4

and 2.5% C) A I-I -723.0 Kcallkg. It i s natural that oxidic and sulphated dust in circulation greatly disturbs the combustion reactions in the reaction shaft and increases the amount of additional fuel.

Appendix 1 Amounts and analyses of products of flash smelting process test operations Component Amount Analysis weight-% Example kg/h Cu Fe Co Ni Zn S 0 S10,

, tvins Exam Tfi 93.6 18.37 27.36 0.16 0.11 4.76 3.32 (12.4) 25.50 Example "-1 99.8 17.23 25.66 0.15 0.11 4.47 18.29 2.7) 23.91 Example Il-Z 81.7 17.95 30.79 0.15 0.11 5.89 21.50 3.2) 14.26 Example II-4 85.8 17.10 29.34 0.15 0.10 5.61 28.23 0.0) 13.59 Example Ill-1 80.0 17.95 28.57 0.15 0.11 7.96 21.13 3.2) 14 79 Sla if Example l-l 331.4 3.35 46.00 0.25 0.06 1.10 0.27 27.43 Example II-Z 328.7 0.50 46.06 0.27 0.08 1.11 0.80 28 76 Example III-l 324.1 0.54 45.68 0.26 0.08 2.19 0.75 28:53

Amounts and analyses of products of flash smelting process test operations Component Amount Analysis weight-% Example kg/h Cu Fe Co Ni Zn S O SiO Matte Example 1- 82.7 76.60 2.50 0.06 0.21 0.24 19.55 0.28 0.15 Example lI-2 99.0 76.10 3.15 0.06 0.24 0.28 19.50 0.32 0.20 Example 111-1 96.6 77.40 2.15 0.05 0.25 g 0.21 19.49 0.21 0.15

Example Sampling point 1-1 Conventional smelting method Shaft (g) Shaft (h) Rising tube (k) "-1 Partial reduction in rising tube Rising tube (k) 11-2 Partial reduction in lower furnace and rising tube Rising tube (k) "-3 Partial reduction in lower furnace and rising tube Rising tube (k) "-4 Complete reduction in rising tube Rising tube (k) "-5 Complete reduction in rising tube Rising tube (k) 111 1 Circulating flying dust load Rising tube (k) 1300 1789.3 1.39X10" 9.81Xl0 Example Sampling point Gas phase of flash smelting process test operations Feeding of materials to gas phase kg/h C H N,

H Conventional smelting method Shaft (g) Shaft (h) Rising tube (k) "-1 Partial reduction in rising tube (k) 11-2 Partial reduction in lower furnace and rising tube Rising tube (k) 11 3 Partial reduction in lower furnace and rising tube Rising tube (k) "-4 Complete reduction in rising tube Rising tube (k) "-5 Complete reduction in rising tube Rising tube (k) 111-1 Circulating flying dust load Rising tube (k) Example Sampling Point oas'piisi flash smelting process test operations 1 Composition of gas phase vo1-% dry analysis H, 11,5 CO COS CO, SO, N,

l-l Conventional smelting method Shaft (g) Shaft (h) Rising tube (k) Example Sampling Point Appendix ll-Continucd Gas phase of flash smelting process test operation Composition of gas phase vo1-% H, 11 5 CO dry analysis COS "-1 Partial reduction in rising tube Rising tube (k) "-2 Partial reduction in lower furnace and rising tube Rising tube (k) "-3 Partial reduc tion in lower furnace Heat balances of flash smelting process test operations Appendix [11 1 Conventional smelting "-1 Reduction in rising Example method tube Balance Component Tempera- Amount Amount Tempera- Amount Amount ture "C of maof heat ture "C of maof heat terial Mcal/h terial v Mcal/h kg-Nm /h kg-Nm /h Cu concentrate 25 503.0 497.5 25 503.0 497.5 Sand 25 89.6 25 89.6 Butane 25 65.9 719.6 25 82.8 904.5 reaction shaft 500 984.2 150.9 500 984.2 150.9 lower furnace 25 504.3 25 504.3 In total 1368.0 1552.9 Out Matte 1275 82.7 63.4 1275 82.7 63.4 Slag 1310 331.4 101.6 1310 331.4 101.6 Flying dust 1300 93.6 22.5 1250 99.8 85.6 Gas phase 1300 1511.8 747.8 1250 1553.8 864.2 Losses of heat 435.0 435.0 Out total 1370.3 1549.8 Difference: 1n Out 2.3 +3.1

Heat balances of flash smeltin rocess test operations 'me'ductiofi'filbT/Effiiffiiih'd rising tube Reduc ionin lower furnace a and l'lSll'lg tube Example Balance component Tempera- Amount Amount Tempera- Amount Amount ture "C of maof heat ture C of maof heat terial Mcal/h terial Mcal/h kg-Nm"/h kg-Nm /h C ncen r 25 503.0 497.5 25 503.0 497.5 Sand 25 79.9 25 79.9 Butane 25 85.2 930.3 25 98.2 1072.3

Air

reaction shaft 500 150.9 500 984.2 150.9 lower furnace 25 25 504.3 In total 1578.7 1720.7

Out

Matte 1275 99.0 77.9 1275 99.0 77.9 Slag 1300 328.7 117.3 1300 328.7 117.3 Flying dust 1250 81.7 78.2 1250 85.8 96.9 Gas phase 12.50 1559.9 868.1 1250 1588.9 988.1 Losses of heat 435.0 435.0 Out total 1576.5 1715.2 Difference: 1n Out +2.2 +5.5

, Heat balangesofflashsmelting process test Operations "-4 Complete (gas) reduction "-5 Complete (gas) re- Example duction Balance component Tempera- Amount Amount Tempera- Amount Amount ture C of maof heat ture "C of maof heat teri l M l/h terial Meal/h kg-Nm-lh kg-Nm'Vh Cu concentrate 25 503.0 497.5 25 503.0 497.5 Sand 25 79.9 25 79.9

Appendix 1ll-C0ntinued Heat balances ofl'lasllsmgltingprocess test operations 11-4 Complete (gas) reduction Co ple (g Example duction Balance component Tempera- Amount Amount Tempera- Amount Amount ture "C of maof heat ture C of maof heat terial Meal/h terial Meal/h kg-Nm' /h kg-Nm"'/h Butane 111.2 1214.3 25 123.8 1351.8 Air reaction shaft 500 984.2 150.9 500 984.2 150.9 lower furnace 25 504.3 25 655.5 In total 1862.8 2000.2 Out I Matte 1275 99.9 77.9 1275 99.0 77.9 Slag 1300 328.7 117.3 1310 328.7 118.1 Flying dust 1250 85.8 96.8 1300 85.8 97.6 Gas phase 1250 1622.8 1145.3 1300 1789.3 1274.2 Losses of heat 435.0 435.0 Out total 1872.3 2002.8 Difference: In Out 9.5 2.6

Heat balances of flash smelting process test operations E l 111 Circulating flying dust load Balance Component Temperature Amount of material Amount of heat "C kg-Nm/h Meal/h Cu Concentrate 25 500.0 466.7 Sand 25 71.0 B tane 25 84.5 922.7 Air I reaction shaft 500 150.9 lower shaft 25 In total 1540.3 Out Matte 1275 96.6 74.4 Slag 1300 324.0 114.1 Flying dust 1250 80.0. 74.3 Gas phase 1250 1516.3 839.0 Losses of heat 435-0 Out total 1536-3 Difference: 1n Out "We'd gm?" 4. An improved method as recited in claim 1, m

1. An improved method of flash smelting sulphide ores in a furnace, in which a fine-grained concentrate is suspended into a heated downward flow of an oxygen containing gas at a temperature of from 1200C to about 1400C in a vertical reaction shaft to oxidize the non-oxidic metal compounds in the concentrate and separate the gases and the flue dust from the solids, which solids form a matte and a slag thereon, and including increasing the ratio of the partial pressure of sulphur to the partial pressure of oxygen in the gases obtained from the oxidizing smelting in the vertical reaction shaft sufficiently to convert the metal oxides of the flue dust into corresponding metal sulphides and to retain the major part of the iron contained in the slag in a bivalent state, and then leading the gases off through the uptake shaft, the gases having been so reduced that ratio by volume (H, H,S C0 COS)/2SO i s less than or approximately equal to 1 in the uptake tube.

2. An improved method as recited in claim 1, in which a fuel is dispersed into the gases emerging from the reaction shaft to decrease the partial pressure of the oxygen and reduce so much sulphur dioxide to sulphur that the partial pressure of the sulphur is at least as high as the dissociation pressure of the sulphur in the sulphur compounds of metals.

3. An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that the oxidic non-ferrous metal compounds contained in the slag are reduced into corresponding metals and metal sulphides.

which the gases emerging from the reaction shaft are reduced to such an extent that the oxidation of the ferrous oxide in the slag is prevented, formed Pe o is reduced and the iron retains bivalent.

5. An improved method as recited in claim 1, in which the flying dust is separated from the gases after the furnace and used as fuel in flash smelting.

6. An improved method as recited in claim 1, in which the components of the flue dust are separated from each other by flotation.

7. An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that at least a part of the sulphur content of the gases is recovered in the form of elemental sulphur.

8. An improved method as recited in claim 1, in which the reduction of the gases emerging from the reaction shaft is regulated to adjust the SO, content in theexhaust gases.

9. improved method as recited in claim 1, in which the smelting in the reaction shaft is carried out in a strongly oxidizing manner so that a matte rich in metal is obtained and the reduction of the oxygen containing emerging from the reaction shaft is then carried out to such an extent that losses of metal from the matte into the slag are prevented from growing greater than with conventional metal contents in the matte, and thus the slag to be blown in a converter is decreased. 

2. An improved method as recited in claim 1, in which a fuel is dispersed into the gases emerging from the reaction shaft to decrease the partial pressure of the oxygen and reduce so much sulphur dioxide to sulphur that the partial pressure of the sulphur is at least as high as the dissociation pressure of the sulphur in the sulphur compounds of metals.
 3. An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that the oxidic non-ferrous metal compounds contained in the slag are reduced into corresponding metals and metal sulphides.
 4. An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that the oxidation of the ferrous oxide in the slag is prevented, formed Fe3O4 is reduced and the iron retains bivalent.
 5. An improved method as recited in claim 1, in which the flying dust is separated from the gases after the furnace and used as fuel in flash smelting.
 6. An improved method as recited in claim 1, in which the components of the flue dust are separated from each other by flotation.
 7. An improved method as recited in claim 1, in which the gases emerging from the reaction shaft are reduced to such an extent that at least a part of the sulphur content of the gases is recovered in the form of elemental sulphur.
 8. An improved method as recited in claim 1, in which the reduction of the gases emerging from the reaction shaft is regulated to adjust the SO2 content in the exhaust gases.
 9. An improved method as recited in claim 1, in which the smelting in the reaction shaft is carried out in a strongly oxidizing manner so that a matte rich in metal is obtained and the reduction of the oxygen containing emerging from the reaction shaft is then carried out to such an extent that losses of metal from the matte into the slag are prevented from growing greater than with conventional metal contents in the matte, and thus the slag to be blown in a converter is decreased. 